Liquid injection device and medical apparatus

ABSTRACT

A liquid injection device includes an injection unit which injects a liquid, a liquid supply instrument which supplies the liquid to the injection unit, and a control unit which controls operation of the injection unit and the liquid supply instrument, wherein the injection unit includes a distal end portion where a nozzle for injecting the liquid is formed, and a body portion in which the distal end portion is removably loaded, at the distal end portion, a distal end-side memory is provided in which first startup data is written, and the control unit is a control unit which reads and writes the first startup data from and to the distal end-side memory in the distal end portion loaded in the body portion and manages use time of the distal end portion based on the first startup data that is read out.

BACKGROUND

1. Technical Field

The present invention relates to a liquid injection device which injectsa liquid from a nozzle to incise or excise a living tissue.

2. Related Art

A liquid injection device which injects a liquid such as water orphysiological saline solution toward a living tissue and thus incises orexcises the living tissue is developed. In a surgical operation usingsuch a liquid injection device, only a tissue of an internal organ orthe like can be selectively incised or excised without damaging nervesand blood vessels. Therefore, the burden on the patient can be reduced.

Also, a liquid injection device which injects a liquid in a pulsedmanner instead of continuously injecting a liquid from a nozzle and thuscan incise or excise a living tissue with a small amount of injection isproposed (JP-A-2008-82202). In this liquid injection device, a liquid issupplied to a liquid chamber using a supply pump and the volume of theliquid chamber is reduced to pressurize the liquid, thus injecting theliquid from a nozzle in a pulsed manner.

These liquid injection devices have an injection unit (hereinafterreferred to as an applicator) in which a nozzle for injecting the liquidis formed and which an operator holds in his or her hand to operate, asupply pump for supplying the liquid to the applicator, a connectiontube connecting the supply pump with the applicator, and the like. Also,a liquid chamber connected to the nozzle, an actuator which deforms theliquid chamber to reduce the volume of the liquid chamber, and the likeare provided within the applicator of the liquid injection device whichinjects the liquid in a pulsed manner.

However, such a liquid injection device has the following problem. Thatis, in the applicator, the inside liquid contacts the outside air at thepart of the nozzle. Therefore, if the absence of injection of the liquidcontinues, the outside air may enter the inside of the applicator fromthe part of the nozzle. Consequently, there is a problem that variousbacteria can propagate within the applicator over a long period of time.

SUMMARY

An advantage of some aspects of the invention is that for a liquidinjection device which injects a liquid from a nozzle of an applicator,a technique which can prevent propagation of various bacteria within theapplicator can be provided.

An aspect of the invention is directed to a liquid injection deviceincluding an injection unit which injects a liquid, a fluid supplyinstrument which supplies the liquid to the injection unit, and acontrol unit which controls operation of the injection unit and theliquid supply instrument. The injection unit includes a distal endportion where a nozzle for injecting the liquid is formed, and a bodyportion in which the distal end portion is removably loaded. At thedistal end portion, a distal end-side memory is provided in which firststartup data, which is data related to date and time when the liquidinjection device is started up for the first time as the distal endportion is loaded in the body portion, is written. The control unit is acontrol unit which reads and writes the first startup data from and tothe distal end-side memory in the distal end portion loaded in the bodyportion and manages use time of the distal end portion based on thefirst startup data that is read out.

In the liquid injection device according to this aspect, the injectionunit which injects the liquid is divided into the distal end portion andthe body portion. The nozzle is formed at the distal end portion and thedistal end portion is removably provided in the body portion. Also, thememory (distal end-side memory) is loaded in the distal end portion. Inthis memory, data (first startup data) about the date and time when theoperator (user) of the liquid injection device starts up, for the firsttime, the liquid injection device with the distal end portion loaded inthe body portion, is written. The first startup data is sufficient ifthe first startup data can specify the date and time when the liquidinjection device is started up for the first time as the distal endportion is loaded in the body portion, and the first startup data doesnot necessarily have to be data of the very date and time. For example,if the time elapsed since the liquid injection device is started up forthe first time as the distal end portion is loaded in the body portionis known, the date and time when the liquid injection device is startedup for the first time can be specified by retrospectively tracing backfrom the current date and time. Therefore, the time elapsed can be usedas the first startup data. The control unit of the liquid injectiondevice reads and writes the first startup data from and to the distalend-side memory of the distal end portion loaded in the body portion,and manages the use time of the distal end portion based on the firststartup data that is read out. For example, if the distal end portion isleft attached to the body portion over a long period of time, theoperator of the liquid injection device can be notified to that effect.As a form of notification, the date and time when the distal end portionis used for the first time after being loaded in the body portion can bedisplayed, thus notifying the operator that there is already a lapse ofa long time since the start of the use of the distal end portion.Alternatively, the time elapsed since the use of the distal end portionis started may be displayed. Moreover, a sound such as a buzz may beoutputted, or a lamp may be switched on or flashed. Of course, if thedistal end portion is left attached to the body portion over anexcessively long time, measures for not only notifying the operator tothat effect but also restraining the startup of the liquid injectiondevice may be taken.

Thus, the distal end portion is replaced before being left attached overa long period of time, and therefore growth of various bacteria insideis prevented. A distal end-side memory is also loaded in the newlyarranged distal end portion. Therefore, the control unit of the liquidinjection device can manage the use time of the distal end portion bywriting first startup data into the distal end-side memory when theliquid injection device is started up for the first time as this distalend portion is loaded.

In the liquid injection device according to the above aspect, number oftimes of startup data (data related to the number of times the liquidinjection device is started up as the distal end portion is loaded) maybe written in the distal end-side memory, in addition to the firststartup data. The number of times of startup data may be data related tothe number of times the liquid injection device is started up as thedistal end portion is loaded, and the number of times of startup datadoes not necessarily have to be data indicating the very number oftimes. For example, by adding the date and time when the liquidinjection device is started up as the distal end portion is loaded(startup date and time), the number of times of startup can be specifiedbased on the number of startup dates and times stored in the distalend-side memory. Of course, the number of times of startup stored in thedistal end-side memory may be updated every time the liquid injectiondevice is started up. The control unit of the liquid injection devicemay manage the use time of the distal end portion based on the firststartup data and the number of times of startup data read out from thedistal end-side memory.

It can be considered that the fact that the liquid injection device isstarted up several times in the state where the distal end portion isloaded in the body portion instrument that the distal end portion isreused. As the distal end portion is reused, there is a greater risk ofgrowth of various bacteria inside, than in the case where the distal endportion is used continuously. Therefore, by storing not only the firststartup data but also the number of times of startup data in the distalend-side memory and managing the use time of the distal end portionbased on these data, it is possible to avoid the growth of variousbacteria within the distal end portion more securely.

The liquid injection device according to the above aspect may beconfigured as follows. First, a liquid chamber to which the liquid issupplied from the liquid supply instrument and which is connected to thenozzle may be provided in the distal end portion. Also, a piezoelectricelement which deforms according to a voltage of an applied drive signaland changes a volume of the liquid chamber may be provided in the bodyportion. Then, by applying the drive signal to the piezoelectric elementto reduce the volume of the liquid chamber in the state where the liquidis supplied to the liquid chamber from the liquid supply instrument, theliquid may be injected from the nozzle in a pulsed manner. A memory(body-side memory) may be loaded in the body portion of the liquidinjection device configured in this manner, and data (drive time data)related to a drive time during which the drive signal is applied to thepiezoelectric element may be stored in the body-side memory. The drivetime data may be data in which a finalized drive time is additionallystored every time the liquid injection device is stopped and thus thedrive time is finalized (data indicating the drive time for everystartup), or may be data in which a cumulative value of these drivetimes is stored. The control unit may manage use time of the bodyportion based on the drive time data read out from the body-side memory.

Thus, the use time of the body portion can be managed in such a way thatthe drive time of the piezoelectric element loaded in the body portiondoes not exceed a predetermined time. Therefore, the body portion of theliquid injection device can be replaced before any trouble occurs in amoving part incorporated in the body portion in order to inject theliquid in a pulsed manner. Of course, since the distal end portion canbe replaced before the body portion is replaced, the growth of variousbacteria within the distal end portion can be avoided.

In the liquid injection device according to the above aspect whichinjects the liquid in a pulsed manner, data about the number of timesthe piezoelectric element is driven (the number of times the drivesignal is applied to the piezoelectric element) (number of times ofdriving data) may be stored in the body-side memory. The number of timesof driving data may be data in which the finalized number of times ofdriving is additionally stored every time the liquid injection device isstopped and thus the number of times of driving is finalized, or may bedata in which a cumulative value of these numbers of times of driving isstored. The control unit may manage the use time of the body portionbased on the number of times of driving data read out from the body-sidememory.

Thus, the use time of the body portion can be managed in such a way thatthe number of times the piezoelectric element loaded in the body portionis driven does not exceed a predetermined number of times. Therefore,the body portion of the liquid injection device can be replaced beforeany trouble occurs in a moving part incorporated in the body portion inorder to inject the liquid in a pulsed manner. Of course, since thedistal end portion can be replaced before the body portion is replaced,the growth of various bacteria within the distal end portion can beavoided.

In the liquid injection device according to the above aspect in whichthe number of times of driving is stored in the body-side memory, thenumber of times of driving data related to the number of times thepiezoelectric element is driven and the voltage of the drive signalapplied to the piezoelectric element may be stored. For example, twotypes of data, that is, data of the number of times the piezoelectricelement is driven and data of the voltage of the drive signal, can bestored as the number of times of driving data. Alternatively, the numberof times of driving data maybe stored in the form of data of the numberof times of driving that is weighted according to the voltage of thedrive signal, instead of directly storing the data of the number oftimes the piezoelectric element is driven.

Thus, the use time of the body portion can be managed in considerationof the amount of deformation of the piezoelectric element (voltage ofthe drive signal) as well as the number of times the piezoelectricelement is driven. Therefore, the occurrence of any trouble in a movingpart incorporated in the body portion during the use of the liquidinjection device can be avoided more securely.

The liquid injection device according to the above aspect can beutilized for a surgical instrument for incising or excising a livingtissue by injecting a liquid to the living tissue. The liquid injectiondevice can also be utilized as a treatment instrument which injecting amedical fluid to a living tissue. Therefore, the liquid injection deviceaccording to the above aspect can be suitably applied as a medicalapparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is an explanatory view showing the schematic configuration of aliquid injection device according to an embodiment.

FIGS. 2A and 2B are explanatory views showing the way a distal endportion is attached to a body portion of an applicator.

FIGS. 3A and 3B are sectional views showing the detailed configurationof the applicator.

FIG. 4 is an explanatory view illustrating a drive signal applied to apiezoelectric element.

FIG. 5 is a block diagram showing the configuration of a control unit.

FIG. 6 is a flowchart showing use time management processing carried outby the control unit.

FIG. 7 is a flowchart showing processing on startup, carried out in theuse time management processing.

FIG. 8 is an explanatory view illustrating the way data is stored in abody-side memory.

FIG. 9 is an explanatory view illustrating a weighting coefficient thatis set according to the voltage of a drive signal.

FIG. 10 is an explanatory view illustrating the way data is stored in adistal end-side memory.

FIG. 11 is an explanatory view illustrating another example of the waydata is stored in the distal end-side memory.

FIG. 12 is a flowchart showing processing during operation, carried outin the use time management processing.

FIGS. 13A and 13B are explanatory views showing a method of calculatinga use equivalent time of the distal end portion.

FIG. 14 is a flowchart showing processing on stop, carried out in theuse time management processing.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, in order to clarify the contents of the invention, anembodiment is described in the following order.

A. Configuration of Device:

-   -   A-1. Configuration of Liquid Injection Device:    -   A-2. Configuration of Applicator:    -   A-3. Configuration of Control Unit:

B. Use Time Management Processing:

-   -   B-1. Processing on Startup:    -   B-2. Processing during Operation:    -   B-3. Processing on Stop:

A. Configuration of Device A-1. Configuration of Liquid Injection Device

FIG. 1 is an explanatory view showing the schematic configuration of aliquid injection device 10 according to this embodiment. The liquidinjection device 10 shown in FIG. 1 is used for a surgical techniquewhere a liquid such as water or physiological saline solution isinjected toward a living tissue to incise or excise the living tissue.

As shown in FIG. 1, the liquid injection device 10 of this embodimentincludes an applicator 100 which an operator holds in his or her handand operates to inject a liquid, a liquid supply instrument 300 whichsupplies the liquid to the applicator 100, a liquid container 306 whichaccommodates the liquid to be injected, a control unit 200 whichcontrols operation of the applicator 100 and the liquid supplyinstrument 300, and the like. In this embodiment, the applicator 100 isequivalent to the “injection unit” according to the invention.

The applicator 100 roughly includes a body portion 110, a distal endportion 120 removably attached to the body portion 110, and the like. Aliquid injection pipe 124 is provided standing in the distal end portion120. A nozzle 122 is formed at a distal end of the liquid injection pipe124. Also, a liquid chamber 126 filled with a liquid is provided on theside of the distal end portion 120 that is attached to the body portion110. This liquid chamber 126 is connected to the nozzle 122 via theliquid injection pipe 124 and is also supplied with a fluid from asecond connection tube 304. Moreover, a piezoelectric element 112 formedby a multilayer-type piezoelectric element is provided in the bodyportion 110. As will be described in detail later, as the distal endportion 120 is attached to the body portion 110 and a drive signal isapplied to the piezoelectric element 112, the piezoelectric element 112expands and contracts, thus changing the volume of the liquid chamber126. Consequently, the liquid in the liquid chamber 126 is injected in apulsed manner from the nozzle 122. Although the liquid injection device10 of this embodiment is described as injecting the liquid in a pulsedmanner from the nozzle 122, the liquid injection device may inject theliquid continuously from the nozzle 122. The detailed configuration ofthe applicator 100 will be described later.

The liquid supply instrument 300 is connected to the liquid container306 via a first connection tube 302 and supplies the liquid sucked fromthe liquid container 306 to the liquid chamber 126 of the applicator 100via the second connection tube 304. The liquid supply instrument 300 ofthis embodiment is configured in such a way that two pistons slide incylinders. By properly controlling the moving speed of the two pistons,it is possible to feed the liquid in a pressurized state toward theapplicator 100 under a predetermined pressure.

A-2. Configuration of Applicator

FIGS. 2A and 2B are explanatory views showing the way the distal endportion 120 is attached to the body portion 110 of the applicator 100.As shown in FIG. 2A, plural (in the illustrated example, three) femalelock parts 110L are provided at equal intervals on an outer peripheralsurface of the body portion 110, and plural (in the illustrated example,three) male lock parts 120L are provided at equal intervals on an outerperipheral surface of the distal end portion 120. To attach the distalend portion 120 to the body portion 110, the distal end portion 120 ismade to abut on a joint surface 110 s of the body portion 110 in such away that the male lock parts 120L are not situated at the same positionsas the female lock parts 110L. After that, as shown in FIG. 2B, thedistal end portion 120 is turned counterclockwise, with the distal endportion 120 kept abutting on the body portion 110. Thus, the male lockparts 120L formed on the distal end portion 120 engage with the femalelock parts 110L on the body portion 110, enabling the distal end portion120 to be firmly attached to the body portion 110. Meanwhile, to detachthe distal end portion 120 from the body portion 110, the distal endportion 120 is turned clockwise. Thus, the male lock parts 120L aredisengaged from the female lock parts 110L, enabling the distal endportion 120 to be detached from the body portion 110.

In this embodiment, a memory is arranged within the distal end portion120, as described below. Moreover, a connection terminal 114 is providedon the joint surface 110 s of the body portion 110. As the distal endportion 120 is attached to the body portion 110, data in the memory ofthe distal end portion 120 can be read out or data can be writtentherein via the connection terminal 114.

FIGS. 3A and 3B are sectional views showing the detailed configurationof the applicator 100. FIG. 3A shows the state where the distal endportion 120 is detached from the body portion 110. FIG. 3B shows thestate where the distal end portion 120 is attached to the body portion110. As shown in FIG. 3A, in the body portion 110, a shallow circularrecessed part 111 is formed on the inner side of the joint surface 110 swith the distal end portion 120 (see FIG. 2A) and a circular diaphragm110 d made of a thin metal plate is attached to a center position of therecessed part 111. On the back side of the diaphragm 110 d, thepiezoelectric element 112 is adhesively attached via a circularreinforcing plate 116. Also, a body-side memory 110 m is arranged withinthe body portion 110. The body-side memory 110 m is connected to thecontrol unit 200 via wiring, not shown.

In the distal end portion 120, a shallow circular recessed shape isformed at a center position on the side to be joined with the bodyportion 110, and this recessed opening is covered with a highly elasticthin film 128 made of a silicone resin or the like, thus forming theliquid chamber 126. The liquid chamber 126 is connected to the secondconnection tube 304 via an inlet flow passage 126 i and is alsoconnected to the liquid injection pipe 124 via an outlet flow passage126 o. The nozzle 122 is attached to the distal end of the liquidinjection pipe 124, and a liquid injection opening 122 o for injectingthe liquid is opened in the nozzle 122.

The part where the liquid chamber 126 is formed in the distal endportion 120 is formed as an inro-style fitting with the recessed part111 of the body portion 110. As distal end portion 120 is attached tothe body portion 110 and the male lock parts 120L are engaged with thefemale lock parts 110L, as shown in FIG. 3B, the thin film 128 of theliquid chamber 126 tightly contacts the diaphragm 110 d of the bodyportion 110. Therefore, as a drive signal is applied to thepiezoelectric element 112 in the state where the distal end portion 120is attached to the body portion 110, the piezoelectric element 112expands and thus deforms the thin film 128 via the reinforcing plate 116and the diaphragm 110 d. Consequently, the volume of the liquid chamber126 is reduced and the liquid within the liquid chamber 126 ispressurized. The liquid is injected in a pulsed manner from the nozzle122 via the outlet flow passage 126 o and the liquid injection pipe 124.

Also, a distal end-side memory 120 m is arranged within the distal endportion 120. As the distal end portion 120 is attached to the bodyportion 110, the distal end-side memory 120 m is connected to thecontrol unit 200 via wiring, not shown, and via the connection terminal114 shown in FIG. 2A.

FIG. 4 is an explanatory view illustrating a drive signal applied to thepiezoelectric element 112. The drive signal rises by a voltage V from aninitial voltage (here, voltage 0) and then falls to the initial voltageagain. As the applied voltage rises, the piezoelectric element 112expands and thus reduces the volume of the liquid chamber 126. Here, theamount of expansion of the piezoelectric element 112 (hence the amountof volume reduction of the liquid chamber 126) is substantiallyproportional to the amount of rise of the applied voltage. Therefore,the liquid of a volume corresponding to the amount of voltage rise(here, voltage V) from the initial voltage is injected from the nozzle122. Hereinafter, the amount of voltage rise (here, voltage V) from theinitial voltage is referred to as a “drive voltage”. In this embodiment,such a drive signal is applied to the piezoelectric element 112 on apredetermined cycle T. Hereinafter, the reciprocal number of the cycle Tis referred to as a “drive frequency”. The drive frequency representsthe number of times of driving per second.

A-3. Configuration of Control Unit

FIG. 5 is an explanatory view showing the schematic configuration of thecontrol unit 200. In the control unit 200, a processing unit 202, anaudio output unit 204, a drive unit 206, a communication unit 208, atime management unit 210 and the like are provided. The audio outputunit 204 has a function of outputting a sound such as a buzz. The driveunit 206 outputs the drive signal shown in FIG. 4 to the piezoelectricelement 112 of the applicator 100 and outputs a control signal tocontrol the operation of the liquid supply instrument 300, to the liquidsupply instrument 300. The communication unit 208 reads data from andwrites data into the body-side memory 110 m in the body portion 110 andthe distal end-side memory 120 m in the distal end portion 120. The timemanagement unit 210 has a so-called timer function and a function ofdetecting the current time. Moreover, the processing unit 202 centrallycontrols the audio output unit 204, the drive unit 206, thecommunication unit 208 and the time management unit 210 and executesvarious kinds of processing for the liquid injection device 10 tooperate properly.

As described above, in the liquid injection device 10 of thisembodiment, the distal end portion 120, which is a portion through whichthe liquid passes in the applicator 100, is attachable to and removablefrom the body portion 110. Although various bacteria can grow in theportion through which the liquid passes if the liquid remains attachedto this portion over a certain period of time after the use of theliquid injection device 10, the applicator 100 can be kept clean byreplacing the distal end portion 120 alone. However, if the distal endportion 120 continues being used for a certain reason, for example, asthe operator of the liquid injection device 10 forgets to replace thedistal end portion 120, various bacteria can grow inside the applicator100. Thus, in order to avoid such a situation, the following processingis carried out in the liquid injection device 10 of this embodiment.

B. Use Time Management Processing

FIG. 6 is a flowchart of use time management processing executed by theprocessing unit 202 of the control unit 200 in order to manage the usetime of the distal end portion 120. This processing is started as theoperator of the liquid injection device 10 starts up the liquidinjection device 10, and the processing is executed until the operationof the liquid injection device 10 ends. As the use time managementprocessing is started, processing on startup (step S100) is executedfirst.

B-1. Processing on Startup

FIG. 7 is a flowchart of the processing on startup, carried out by theprocessing unit 202 of the control unit 200 at the startup of the liquidinjection device 10. In the processing on startup, various data storedin the body-side memory 110 m are read out first (step S102).

FIG. 8 is an explanatory view showing the concept of the way variousdata are stored in the body-side memory 110 m. In the liquid injectiondevice 10 of this embodiment, data showing the year, month, day and time(year/month/day/hour/minute) of the date and time when the liquidinjection device 10 is started up, and data such as the drive time,number of times of driving, drive voltage and drive frequency at thattime are stored in the body-side memory 110 m. Here, the drive time isthe time during which the drive signal as shown in FIG. 4 is applied todrive the piezoelectric element 112. More simply, the time from thestartup of the liquid injection device 10 until the liquid injectiondevice 10 is stopped can be used as the drive time. The number of timesof driving refers to the number of times the drive signal as shown inFIG. 4 is applied to the piezoelectric element 112 (in other words, thenumber of times the operation of the piezoelectric element 112 to expandand then return to the original length is repeated). The drive voltageis the voltage difference between an initial voltage and a maximumvoltage of the drive signal. The drive frequency is the reciprocalnumber of the cycle T of the drive signal and shows the number of timesthe drive signal is applied per second (see FIG. 4).

In the example shown in FIG. 8, for example, the data on the top of thedrawing shows that the liquid injection device 10 is started up for thefirst time at hour “hr1”, minute “mn1” on day “da1”, month “mt1”, year“yr1”, and that the drive time at that time is “T1”, the number of timesof driving is “N1”, the drive voltage is “V1” and the drive frequency is“C1”. Also, the liquid injection device 10 is started up twice afterthat, and the date and time of startup, the drive time, the number oftimes of driving, the drive voltage, the drive frequency or the like arestored for startup of each time. In step S102 of FIG. 7, these datastored in the body-side memory 110 m are read out.

From the data shown in FIG. 8, it can be understood that the liquidinjection device 10 is already started up three times. However, thesedata are stored in the body-side memory 110 m arranged within the bodyportion 110 and therefore show the number of times the liquid injectiondevice 10 is started up after the body portion 110 is loaded, to be moreprecise, rather than the number of times the liquid injection device 10is started up.

After the data are readout from the body-side memory 110 m, a cumulativedrive time and a cumulative drive value of the body portion 110 arecalculated (step S104). Here, the cumulative drive time is the total ofthe drive times in the past startup. For example, in the case of thedata shown in FIG. 8, the drive time in the first startup is T1, thedrive time in the second startup is T2, and the drive time in the thirdstartup is T3. Therefore, the total of these “T1+T2+T3” is thecumulative drive time.

The cumulative drive value is the total of the numbers of times ofdriving, weighted according to the drive voltage in the past startup. Inthe case of the data shown in FIG. 8, the number of times of driving isN1 and the drive voltage is V1 in the first startup. In the secondstartup, the number of times of driving is N2 and the drive voltage isV2. In the third startup, the number of times of driving is N3 and thedrive voltage is V3. Therefore, the total of a value K1×N1, which is,the first number of times of driving N1 multiplied by a weightingcoefficient K1 corresponding to the drive voltage V1, a value K2×N2,which is, the second number of times of driving N2 multiplied by aweighting coefficient K2 corresponding to the drive voltage V2, and avalue K3xN3, which is, the third number of times of driving N3multiplied by a weighting coefficient K3 corresponding to the drivevoltage V3, that is, the value “K1×N1+K2×N2+K3×N3” is the cumulativedrive value.

FIG. 9 shows the way the weighting coefficient K is set according to thedrive voltage. In a memory, not shown, arranged within the processingunit 202 of the control unit 200, the corresponding relation between thedrive voltage and the weighting coefficient as shown in FIG. 9 isstored. The meaning of the weighting coefficient K that is set accordingto the drive voltage will be described later.

After the cumulative drive time and the cumulative drive value are thuscalculated (step S104), whether the cumulative drive time exceeds apredetermined allowable time or not is determined (step S106). Here, theallowable time can be described as follows. As described with referenceto FIGS. 3A and 3B, the applicator 100 injects the liquid by expandingthe piezoelectric element 112 and thus reducing the volume of the liquidchamber 126. At this point, the diaphragm 110 d of the body portion 110repeats the operation of deforming as the piezoelectric element 112expands and restoring the original shape as the piezoelectric element112 contracts. Therefore, as the applicator 100 is used over a longperiod of time, the diaphragm 110 d may be cracked or the diaphragm 110d may be less able to restore the original shape even when thepiezoelectric element 112 contracts. Thus, an allowable time duringwhich there is no risk of such situations is determined in advance forthe body portion 110. In step S106 of FIG. 7, whether the cumulativedrive time of the body portion 110 exceeds this allowable time or not isdetermined.

If the cumulative drive time exceeds the allowable time as a result ofthe determination (step S106: yes), the audio output unit 204 outputs asound such as a predetermined buzz and thus issues a warning (stepS108). Therefore, when a buzz is outputted at startup, the operator ofthe liquid injection device 10 can recognize that the use time of thebody portion 110 of the applicator 100 exceeds the allowable time andthat the body portion 110 needs to be replaced. As described above,since the allowable time is the time during which there is no risk ofproblems such as cracking of the diaphragm 110 d of the body portion110, the cumulative drive time exceeding the allowable time does notnecessarily instrument that a problem immediately occurs with the bodyportion 110. Moreover, there maybe some cases where a surgical operationmust be carried out even though a new body portion 110 is not acquiredyet for some reasons. Thus, the replacement of the body portion 110 isprompted simply by issuing a warning, instead of making the liquidinjection device 10 unavailable for use, even if the cumulative drivetime exceeds the allowable time (step S106: yes).

Meanwhile, if the cumulative drive time of the body portion 110 does notexceed the allowable time (step S106: no), whether the cumulative drivevalue that is previously calculated exceeds a predetermined allowablevalue or not is determined (step S110). Here, the allowable value is thefollowing value. As described above, the diaphragm 110 d of the bodyportion 110 repeats deformation every time the piezoelectric element 112expands or contracts. Therefore, the time when problems occur such as acrack of the diaphragm 110 d or the difficulty of the diaphragm 110 d torestore the original shape is considered to be dependent on the numberof times the diaphragm 110 d is deformed (that is, the number of timesthe piezoelectric element 112 is driven). Also, it is considered that acrack or the like occurs sooner as the amount of each deformation (thatis, the amount of deformation of piezoelectric element 112) is greater.Thus, an allowable value can be considered in such a way that problemsdo not occur if the cumulative value of the number of times thepiezoelectric element 112 is driven, weighted according to the drivevoltage and thus accumulated, does not exceed a certain value. Theallowable value of the cumulative drive value is such a value. Also, theweighting coefficient K shown in FIG. 9 is a weighting coefficient addedto the number of times of driving in consideration of the influence ofthe drive voltage when the number of times of driving is accumulated.

In step S110 of FIG. 7, whether the cumulative drive value of the bodyportion 110 exceeds this allowable value or not is determined. If thecumulative drive value exceeds the allowable value as a result of thedetermination (step S110: yes), the audio output unit 204 outputs asound such as a predetermined buzz and thus issues a warning (stepS112), as in the case where it is determined in step S106 that thecumulative drive time exceeds the allowable time. Consequently, theoperator of the liquid injection device 10 can recognize that the bodyportion 110 of the applicator 100 needs to be replaced. The buzz that isoutputted when the cumulative drive time exceeds the allowable time(step S106: yes) and the buzz that is outputted when the cumulativedrive value exceeds the allowable value (step S110: yes) can be thesame. Meanwhile, if the cumulative drive value does not exceed theallowable value (step S110: no), no warning is issued.

After the cumulative drive time and the cumulative drive value of thebody portion 110 are calculated and a warning is issued when necessary,as described above (steps S104 to S112), information at the time ofstartup (information at startup) is written in the body-side memory 110m (step S114). Here, the information at startup is information such asthe date and time when the liquid injection device 10 is started up andthe drive voltage, drive frequency and the like of the drive signalapplied to the piezoelectric element 112. The date and time when theliquid injection device 10 is started up can be acquired from the timemanagement unit 210 included in the control unit 200. The drive voltage,drive frequency and the like are set by the operator when starting upthe liquid injection device 10. Subsequently, the processing unit 202 ofthe control unit 200 this time reads out data stored in the distalend-side memory 120 m of the distal end portion 120 (step S116).

FIG. 10 is an explanatory view showing the concept of the way data arestored in the distal end-side memory 120 m. As shown in FIG. 10, thedate and time when the distal end portion 120 is started up in the past(to be more precise, the date and time when the liquid injection device10 is started up, with the distal end portion 120 loaded in the bodyportion 110) is stored in the distal end-side memory 120 m. For example,in the example shown in FIG. 10, the current distal end portion 120 isstarted up for the first time at hour “hr1”, minute “mn1” on day “da1”,month “mt1”, year “yr1”, and subsequently started up twice (three timesif the first time is included) Thus, the processing unit 202 of thecontrol unit 200 stores the date and time of the first startup and thenumber of times the distal end portion 120 is started up already, intoan internal memory, not shown, of the processing unit 202 (step S118).Then, the current date and time acquired from the time management unit210 is additionally written into the distal end-side memory 120 m. Inthe example shown in FIG. 10, the current date and time is written asthe fourth startup date and time. After that, the processing on startupends and returns to the use time management processing of FIG. 6.

In the above description, it is assumed that the date and time ofstartup of each time is stored in the distal end-side memory 120 m.However, more simply, the date and time of the first startup and thenumber of times of startup in the past maybe stored in the distalend-side memory 120 m. In this case, the following processing is carriedout in step S120 of FIG. 7. That is, if the date and time of the firststartup is not stored in the distal end-side memory 120 m, the currentdate and time is written as the date and time of the first startup.Meanwhile, if the date and time of the first startup is stored in thedistal end-side memory 120 m, the number of times of startup in the paststored in the distal end-side memory 120 m is updated to a value that isgreater by “1”. For example, in the case of the second startup, the dateand time of the first startup and the number of times of startup in thepast (0) are stored in the distal end-side memory 120 m. Thus, the dateand time of the first startup is kept unchanged and the number of timesof driving in the past is updated to a value (1) that is greater by 1.

The data of the date and time of the first startup stored in the distalend-side memory 120 m is equivalent to the “first startup data”according to the invention. In the case where the date and time ofstartup of each time is additionally written in the distal end-sidememory 120 m, as shown in FIG. 10, the number of startup dates and timesstored in the distal end-side memory 120 m expresses the number of timesof startup. Therefore, in such a case, the data of the startup date andtime stored in after the first time is equivalent to the “number oftimes of startup data” according to the invention. On the other hand, inthe case where the number of times of startup in the past is storedinstead of the date and time of startup of each time being additionallywritten in the distal end-side memory 120 m, as shown in FIG. 11, thedata of the number of times of startup in the past is equivalent to the“number of times of startup data” according to the invention.

B-2. Processing during Operation

FIG. 12 is a flowchart of the processing during operation carried out bythe processing unit 202 of the control unit 200. This processing is theprocessing executed subsequently to the processing on startup (stepS100) as shown in FIG. 6.

As the processing during operation (step S200) is started, theprocessing unit 202 first starts clocking a predetermined time, usingthe timer function of the time management unit 210 (step S202). Here, anarbitrary time can be set as the predetermined time by the operator ofthe liquid injection device 10. However, the predetermined time istypically 30 minutes or one hour. Next, whether there is already a lapseof the predetermined time that is set or not is determined (step S204).If there is not a lapse of the predetermined time yet (step S204: no),whether to stop the liquid injection device 10 or not, that is, whethera stop switch, not shown, provided on the liquid injection device 10 isoperated by the operator or not, is determined (step S212). If the stopswitch is not operated as a result of the determination (step S212: no),the processing returns to step S204 and whether there is already a lapseof the predetermined time or not is determined again.

If it is determined that there is a lapse of the predetermined time(step S204: yes) as such a determination is repeated, the processingunit 202 calculates a use equivalent time of the distal end portion 120(step S206). Here, the use equivalent time of the distal end portion 120refers to a time that is calculated based on the time elapsed since thedistal end portion 120 is started up for the first time and inconsideration of the number of times of startup in the past.

FIGS. 13A and 13B are explanatory views showing a method for calculatingthe use equivalent time of the distal end portion 120. FIG. 13A showsthe state of use until now from when the distal end portion 120 is usedfor the first time. FIG. 13B shows the way the use equivalent time iscalculated based on the state of use of the distal end portion 120. Inthe example shown in FIG. 13A, the distal end portion 120 is temporarilystopped after the first startup thereof, and after a while, the distalend portion 120 is started up again. In this case, at the current time,the operation based on the second startup is in progress. Whencalculating the use equivalent time, the processing unit 202 firstcalculates the time elapsed from the date and time of the first startupto the current date and time. The date and time of the first startup isread out from the distal end-side memory 120 m in the foregoingprocessing on startup and stored in the internal memory of theprocessing unit 202 (step S118 of FIG. 7). The current date and time canbe acquired from the time management unit 210.

Next, the number of times the distal end portion 120 is started up inthe past (the number of times of startup in the past) is acquired. Thenumber of times of startup in the past, too, is read out in theforegoing processing on startup and stored in the internal memory of theprocessing unit 202 (step S118 of FIG. 7). In the example shown in FIGS.13A and 13B, since the operation based on the second startup is inprogress at the current time, the number of times of startup in the pastis 1. Then, for each time of the number of times of startup, apredetermined time (for example, four hours) is added to the timeelapsed from the date and time of the first startup to the current dateand time, and the resulting time is regarded as the use equivalent time(see FIG. 13B). Instep S206 of FIG. 12, the use equivalent time of thedistal end portion 120 is calculated in this manner.

Here, the use equivalent time has the following technical significance.First, the use equivalent time becomes longer as a longer time passesfrom the date and time of the first startup, and the use equivalent timealso becomes longer as the number of times of startup in the pastincreases. Also, the risk of various bacteria growing inside the distalend portion 120 becomes higher as a longer time passes from the firstuse of the distal end portion 120. Moreover, the risk of variousbacteria growing inside the distal end portion 120 becomes higher as thenumber of times the distal end portion 120 is reused increases.Therefore, it can be considered that the risk of various bacteriagrowing inside the distal end portion 120 becomes higher as the useequivalent time becomes longer.

Thus, whether the calculated use equivalent time exceeds a presetallowable time of the distal end portion 120 or not is determined (stepS208). If the use equivalent time exceeds the allowable time as a resultof the determination (step S208: yes), the audio output unit 204 outputsa sound such as a predetermined buzz and thus issues a warning (stepS210). On the other hand, if the use equivalent time does not exceed theallowable time (step S208: no), no warning is issued and the processingreturns to step S202 to start clocking a predetermined time.

As is clear from the above description, the use equivalent time is usedas an indicator indicating the risk of various bacteria growing insidethe distal end portion 120. Therefore, the weight on the time elapsedfrom the date and time of the first startup and the number of times ofstartup in the past can be properly changed in such a way that the useequivalent time serves as a more appropriate indicator. For example, inthe calculation, the time elapsed from the date and time of the firststartup may be halved, or a longer time (for example, ten hours) foreach time of the number of times of startup in the past may be adopted.

Also, it is desirable that the buzz that is outputted when the useequivalent time of the distal end portion 120 exceeds the allowable timeis different from the buzz that is outputted when the cumulative drivetime of the body portion 110 exceeds the allowable time or when thecumulative drive value exceeds the allowable value. Thus, simply byhearing the buzz, the operator of the liquid injection device 10 canrecognize that the distal end portion 120 of the applicator 100 needs tobe replaced.

In this way, in the processing during operation, the operation ofcalculating the use equivalent time every time a predetermined timepasses (step S206) and warning the operator to replace the distal endportion 120 (step S210) if the resulting use equivalent time reaches theallowable time (step S208: yes), are repeated until the operator stopsthe liquid injection device 10. Then, as the operator operates the stopswitch on the liquid injection device 10 (step S212: yes), theprocessing during operation ends and returns to the use time managementprocessing of FIG. 6. After that, the following processing on stop (stepS300) starts.

B-3. Processing on Stop

FIG. 14 is a flowchart of the processing on stop, carried out by theprocessing unit 202 of the control unit 200. In the processing on stop,the drive time for which the piezoelectric element 112 is driven and thenumber of times the piezoelectric element 112 is driven during theperiod from the startup to the stop of this time are written into thebody-side memory 110 m (step S302). That is, in step S114 of theprocessing on startup described with reference to FIG. 7, the date andtime of startup and the information at startup such as drive voltage anddrive frequency are written in the body-side memory 110 m, but the drivetime and the number of times of driving at the startup point are notknown and therefore not written. Thus, when the liquid injection device10 is stopped, processing to write the finalized drive time and numberof times of driving into the body-side memory 110 m is carried out. Inthis way, of the data shown in FIG. 8 stored in the body-side memory 110m, the date and time of startup, drive voltage, drive frequency and thelike are written when the liquid injection device 10 is started up, andthe drive time, number of times of driving and the like are written whenthe liquid injection device 10 is stopped. The drive voltage writteninto the body-side memory 110 m when the liquid injection device 10 isstopped is equivalent to the “drive time data” according to theinvention, and the number of times of driving is equivalent to the“number of times of driving data” according to the invention.

Next, the processing unit 202 of the control unit 200 calculates thecumulative drive time and the cumulative drive value of the body portion110 as of the present time, using the data that are already stored inthe body-side memory 110 m and the data that are newly written in thebody-side memory 110 m (step S304). The method of calculating thecumulative drive time and the cumulative drive value is similar to themethod of calculation in step S104 of the processing on startup.

Then, whether the calculated cumulative drive time exceeds an allowabletime or not is determined (step S306). If the cumulative drive timeexceeds the allowable time (step S306: yes), the audio output unit 204outputs a buzz or the like to issue a warning (step S308). Also, whetherthe calculated cumulative drive value exceeds an allowable value or notis determined (step S310) and if the cumulative drive value exceeds theallowable value (step S310: yes), the audio output unit 204 outputs abuzz or the like to issue a warning (step S312). Meanwhile, if the newlycalculated cumulative drive time does not exceed the allowable time(step S306: no) and the newly calculated cumulative drive value does notexceed the allowable value, either (step S310: no), the processing onstop of FIG. 14 ends without issuing a warning and returns to the usetime management processing of FIG. 6. After that, the use timemanagement processing ends, too.

As described above in detail, in the liquid injection device 10 of thisembodiment, the distal end-side memory 120 m is loaded in the distal endportion 120 of the applicator 100. The date and time when the distal endportion 120 is used for the first time (the date and time of firststartup) and the number of times of use in the past (number of times ofstartup) are stored in the distal end-side memory 120 m. After theliquid injection device 10 is started up, the use equivalent time of thedistal end portion 120 is calculated based on the data stored in thedistal end-side memory 120 m and the current time. If the resulting timeexceeds an allowable time, a warning to prompt replacement of the distalend portion 120 is issued every predetermined time period. Therefore,the risk of various bacteria growing inside the distal end portion 120as the operator of the liquid injection device 10 forgets to replace thedistal end portion 120 can be avoided.

Also, the body-side memory 110 m is loaded in the body portion 110 ofthe applicator 100. The data of the drive time, drive voltage, number oftimes of driving and the like of the piezoelectric element 112 arestored in the body-side memory 110 m. When the liquid injection device10 is started up or stopped, the cumulative drive time and thecumulative drive value of the body portion 110 are calculated based onthese data. If the cumulative drive time exceeds an allowable time, orif the cumulative drive value exceeds an allowable value, a warning toprompt replacement of the body portion 110 is issued. Situations such ascracking of the diaphragm 110 d of the body portion 110 while the liquidinjection device 10 is in use can be avoided in advance. In addition tothe drive time, drive voltage, number of times of driving and the likeof the piezoelectric element 112, the date and time of startup of theliquid injection device 10 and the data about the drive frequency of thepiezoelectric element 112 are stored in the body-side memory 110 m.Therefore, even when a certain problem occurs while the liquid injectiondevice 10 is in use, the cause of the problem can be specified bychecking these data stored in the body-side memory 110 m.

The liquid injection device according to the invention is describedabove, using an exemplary embodiment. However, the invention is notlimited to the embodiment and can be carried out in various formswithout departing from the scope of the invention.

For example, in the processing on startup (step S100 and the processingon stop (step S300) in the use time management processing, a warning toreplace the body portion 110 may be issued. When a warning is issued,the fact that the warning is issued or the date and time when thewarning is issued may be stored in the body-side memory 110 m.Similarly, in the processing during operation (step S200), a warning toreplace the distal end portion 120 may be issued. When a warning isissued, the fact that the warning is issued or the date and time whenthe warning is issued may be stored in the distal end-side memory 120 m.

This application is a continuation application of U.S. patentapplication Ser. No. 13/616,884, filed Sep. 14, 2012, which patentapplication is incorporated herein by reference in its entirety. U.S.patent application Ser. No. 13/616,884 claims the benefit of andpriority to Japanese Patent Application No. 2011-227662, filed on Oct.17, 2011, the contents of which are hereby incorporated by reference inits entirety.

1-10. (canceled)
 11. A liquid injection apparatus comprising: aninjection unit which includes a liquid injecting nozzle and an actuatorto inject liquid from the nozzle; and a controller configured to beconnected with the injection unit and to manage a use time of theactuator on the basis of a drive time of the actuator.
 12. The liquidinjection apparatus according to claim 11, wherein the controlleroutputs a warning when the drive time of the actuator exceeds anallowable time.
 13. The liquid injection apparatus according to claim11, wherein the controller configured to manage the use time of theactuator on the basis of a number of times of the actuator is driven.14. The liquid injection apparatus according to claim 13, wherein thecontroller outputs a warning when the number of times of the actuator isdriven exceeds an allowable number of times.
 15. The liquid injectionapparatus according to claim 11, wherein the injection unit includes adistal end portion where the nozzle is formed, a body portion in whichthe distal end portion is removably loaded, and a first memory connectedto the body portion and in which a drive time data related to the drivetime of the actuator is written.
 16. A controller configured to beconnected with a liquid injecting unit which includes a liquid injectingnozzle and an actuator to inject liquid from the nozzle, the controllercomprising: a processor configured to manage a use time of the actuatoron the basis of a drive time of the actuator.
 17. The controlleraccording to claim 16, wherein the processor outputs a warning when thedrive time of the actuator exceeds an allowable time.
 18. The controlleraccording to claim 16, wherein the processor configured to manage theuse time of the actuator on the basis of a number of times of theactuator is driven.
 19. The controller according to claim 18, whereinthe processor outputs a warning when the number of times of the actuatoris driven exceeds an allowable number of times.